Metallocene compound

ABSTRACT

The present invention relates to a metallocene compound of the formula I ##STR1## which can advantageously be used as catalyst component for olefin polymerization.

The invention relates to a metallocene compound which can beadvantageously used for the preparation of polyolefins which cover abroad property spectrum. In addition, the metallocene compound of theinvention has a high polymerization activity in the industriallyinteresting temperature range.

The literature discloses the preparation of polyolefins using solublemetallocene compounds in combination with aluminoxanes or othercocatalysts which, owing to their Lewis acidity, can convert the neutralmetallocene into a cation and stabilize it.

For example, there has been proposed a specific preactivation method forthe metallocene using an aluminoxane, which leads to an increase in theactivity of the catalyst system and to a significant improvement in theparticle morphology of the polymer (cf. EP 0 302 424). Although thepreactivation increases the molecular weight, no significant increasecan be achieved. A further, but still not sufficient, increase in themolecular weight was able to be achieved by use of specificheteroatom-bridged metallocenes at high metallocene activity (EP-A 0 336128).

Furthermore, catalysts based on ethylenebisindenyl hafnium dichlorideand ethylenebis(4,5,6,7-tetrahydro-1-indenyl)hafnium dichloride andmethylaluminoxane are known, by means of which catalysts relativelyhigh-molecular-weight polypropylenes can be prepared by suspensionpolymerization (cf. J. A. Ewen et al., J. Am. Chem. Soc. 109 (1987)6544). However, under industrially relevant polymerization conditions,the particle morphology of the polymers produced in this way is notsatisfactory and the activity of the catalysts used is comparativelylow. Thus, combined with the high catalyst costs, an inexpensivepolymerization is not possible using these systems.

A significant increase in the molecular weight could be achieved by useof metallocenes in which the aromatic π ligands fixed by means of abridge bear substituents in the 2 position (EP 485 822) or in the 2 and4,6 positions (EP 545 303).

To meet the demands of inexpensive large-scale production,polymerization has to be carried out at reaction temperatures which areas high as possible, since at higher polymerization temperatures theheat of polymerization generated can be conducted away using lesscoolant and the reaction can therefore be carried out usingsignificantly smaller dimensions of the cooling water circuit.

In this respect the last-named metallocenes having substituents in the 2or 4 and 6 positions to the bridge are very effective even at apolymerization temperature of 70° C., but nevertheless the achievablemolecular weights at industrially relevant polymerization temperatures(e.g. 70° C.) are still too small for some industrial applications suchas, for example, the preparation of polymers for pipes and large hollowbodies and also specific fibres.

Metallocenes having two substituted cyclopentadienyl π ligands such as,for instance, dimethylsilanediyl(2-methyl-4-t-butyl-1-cyclopentadienyl)₂ZrCl₂ have likewise been proposed as polymerization catalysts (H.-H.Brintzinger et al., Angew. Chem. 102 (1990) 339). However, these systemsare in no way convincing with regard to achievable polymer molecularweight, stereospecificity or polymer melting point; furthermore theirpolymerization activity is very low and the necessary separation of themeso and rac forms obtained from the synthesis is very difficult--highlyisotactic polyolefin can only be prepared using the rac form.Furthermore, the meso form is obtained in about the same amount as therac form, which means that half the chemicals used have to be disposedof and only half the product is usable. EP-A 0 544 308 proposescatalysts having two different π ligands such as, for instance,isopropylidene(4-methyl-1-cyclopentadienyl)(3-t-butyl-1-indenyl)ZrCl₂which, owing to their asymmetry, possess a priori no meso form and thuscircumvent the rac/meso separation problem, but the deficiencies withregard to polymer properties and catalyst activity were not able to besolved. The work of Ewen et al. (J. Am. Chem. Soc. 110 (1988) 6255)likewise discloses catalysts having two different π ligands such as, forinstance, isopropylidene(cyclopentadienyl)(fluorenyl)ZrCl₂. However,these asymmetric compounds produce syndiotactic polyolefins. Thepreparation of isotactic polyolefins is not possible therewith.

It was therefore the object of the invention to provide a catalystsystem which avoids the disadvantages of the prior art and, particularlyat industrially relevant polymerization temperatures, gives with highpolymerization activity, isotactic polyolefins which cover a broadproperty spectrum, in particular with regard to molecular weights andisotacticities.

It has been found that this object can be achieved by means of ametallocene compound having two differing π ligands which aresubstituted in a very particular manner.

Owing to their chemical structure, the metallocenes of the inventionhave no meso form which would have to be separated off in acost-intensive manner, since only atactic polyolefin can be preparedusing meso forms.

In addition, it is possible using the proposed metallocene catalystconcept, by combination of π ligands which have relatively littledifference, to provide an inexpensive-to-prepare range of polymerizationcatalysts for a wide range of polymerization and product requirements.

The invention accordingly provides a metallocene compound of the formulaI ##STR2## where M² is a metal of the group IVb, Vb or VIb of thePeriodic Table,

R¹ and R² are identical or different and are a hydrogen atom, a C₁ -C₁₀-alkyl group, a C₁ -C₁₀ -alkoxy group, a C₆ -C₁₀ -aryl group, a C₆ -C₁₀-aryloxy group, a C₂ -C₁₀ -alkenyl group, a C₇ -C₄₀ -arylalkyl group, aC₇ -C₄₀ -alkylaryl group, a C₈ -C₄₀ -arylalkenyl group or a halogenatom,

R³ are identical or different and are a hydrogen atom, a halogen atom, aC₁ -C₁₀ -alkyl group which can be halogenated, a C₆ -C₁₀ -aryl group, aC₂ -C₁₀ -alkenyl group, a C₇ -C₄₀ -arylalkyl group, a C₇ -C₄₀ -alkyloxygroup, a C₈ -C₄₀ -arylalkenyl group, a --NR₂ ¹⁰, --OR¹⁰, --SR¹⁰, --OSiR₃¹⁰, --SiR₃ ¹⁰ or --PR₂ ¹⁰ radical, where R¹⁰ is a halogen atom, a C₁-C₁₀ -alkyl group or a C₆ -C₁₀ -aryl group,

R⁴ are identical or different and are a hydrogen atom, a halogen atom, aC₁ -C₂₀ -alkyl group, a C₁ -C₂₀ -fluoroalkyl group, a C₆ -C₃₀ -arylgroup, a C₆ -C₃₀ -fluoroaryl group, a C₁ -C₂₀ -alkoxy group, a C₂ -C₂₀-alkenyl group, a C₇ -C₄₀ -arylalkyl group, a C₈ -C₄₀ -arylalkenylgroup, a C₇ -C₄₀ -alkylaryl group, a --NR₂ ¹⁰, --OR¹⁰, --SR¹⁰, --OSiR₃¹⁰, --SiR₃ ¹⁰ or --PR₂ ¹⁰ radical, where R¹⁰ is a halogen atom, a C₁-C₁₀ -alkyl group or a C₆ -C₁₀ -aryl group, or two or more radicals R⁴together with the atoms connecting them form a ring system,

R⁵ is a hydrogen atom, a halogen atom, a C₁ -C₁₀ -alkyl group which canbe halogenated, a C₆ -C₁₀ -aryl group, a C₂ -C₁₀ -alkenyl group, a C₇-C₄₀ -arylalkyl group, a C₇ -C₄₀ -alkyloxy group, a C₈ -C₄₀ -arylalkenylgroup, a --NR₂ ¹⁰, --OR¹⁰, --SR¹⁰, --OSiR₃ ¹⁰, --SiR₃ ¹⁰ or --PR₂ ¹⁰radical, where R¹⁰ is a halogen atom, a C₁ -C₁₀ -alkyl group or a C₆-C₁₀ -aryl group,

R⁶ are identical or different and are a hydrogen atom, a halogen atom, aC₁ -C₂₀ -alkyl group which can be halogenated, a C₆ -C₃₀ -aryl group, aC₂ -C₁₀ -alkenyl group, a C₇ -C₄₀ -arylalkyl group, a C₇ -C₄₀ -alkyloxygroup, a C₈ -C₄₀ -arylalkenyl group, a --NR₂ ¹⁰, --OR¹⁰, --SR¹⁰, --OSiR₃¹⁰, --SiR₃ ¹⁰ or --PR₂ ¹⁰ radical, where R¹⁰ is a halogen atom, a C₁-C₁₀ -alkyl group or a C₆ -C₁₀ -aryl group,

R⁷ is ##STR3## ═BR¹¹, ═AlR¹¹, --Ge--, --Sn--, --O--, --S--, ═SO, ═SO₂ ,═NR¹¹, ═CO, ═PR¹¹ or ═P(O)R¹¹,

where

R¹¹, R¹² and R¹³ are identical or different and are a hydrogen atom, ahalogen atom, a C₁ -C₂₀ -alkyl group, a C₁ -C₂₀ -fluoroalkyl group, a C₆-C₃₀ -aryl group, a C₆ -C₃₀ -fluoroaryl group, a C₁ -C₂₀ -alkoxy group,a C₂ -C₂₀ -alkenyl group, a C₇ -C₄₀ -arylalkyl group, a C₈ -C₄₀-arylalkenyl group, a C₇ -C₄₀ -alkylaryl group, or R¹¹ and R¹² or R¹¹and R¹³ in each case together with the atoms connecting them form aring,

M¹ is silicon, germanium or tin,

R⁸ and R⁹ are identical or different and are a hydrogen atom, a halogenatom, a C₁ -C₂₀ -alkyl group, a C₁ -C₂₀ -fluoroalkyl group, a C₆ -C₃₀-aryl group, a C₆ -C₃₀ -fluoroaryl group, a C₁ -C₂₀ -alkoxy group, a C₂-C₂₀ -alkenyl group, a C₇ -C₄₀ -arylalkyl group, a C₈ -C₄₀ -arylalkenylgroup, a C₇ -C₄₀ -alkylaryl group, or R⁸ and R⁹ together with the atomsconnecting them form a ring,

m and n are identical or different and are zero, 1 or 2, where m plus nis zero, 1 or 2, wherein at least one of the radicals R⁴ and R⁵ is nothydrogen.

Alkyl is straight-chain or branched alkyl. Halogen (halogenated) isfluorine, chlorine, bromine or iodine, preferably fluorine or chlorine.Radicals having the same index can be different.

M² is a metal of the group IVb, Vb or VIb of the Periodic Table, forexample titanium, zirconium, hafnium, vanadium, niobium, tantalum,chromium, molybdenum, tungsten, preferably zirconium, hafnium, titanium,particularly preferably Zr.

R¹ and R² are identical or different and are a hydrogen atom, a C₁ -C₁₀,preferably C₁ -C₃ -alkyl group, a C₁ -C₁₀ -, preferably C₁ -C₃ -alkoxygroup, a C₆ -C₁₀ -, preferably C₆ -C₈ -aryl group, a C₆ -C₁₀ -,preferably C₆ -C₈ -aryloxy group, a C₂ -C₁₀ -, preferably C₂ -C₄-alkenyl group, a C₇ -C₄₀ -, preferably C₇ -C₁₀ -arylalkyl group, a C₇-C₄₀ -, preferably C₇ -C₁₂ -alkylaryl group, a C₈ -C₄₀ -, preferably C₈-C₁₂ -arylalkenyl group or a halogen atom, preferably chlorine.

R³ is hydrogen, a halogen atom, preferably a fluorine, chlorine orbromine atom, a C₁ -C₁₀ -, preferably C₁ -C₄ -alkyl group which can behalogenated, a C₆ -C₁₀ -, preferably C₆ -C₈ -aryl group, a C₂ -C₁₀ -,preferably C₂ -C₄ -alkenyl group, a C₇ -C₄₀ -, preferably C₇ -C₁₀-arylalkyl group, a C₇ -C₄₀ -, preferably C₇ -C₁₂ -alkylaryl group, a C₈-C₄₀ -, preferably C₈ -C₁₂ -arylalkenyl group, a --NR₂ ¹⁰, --SR¹⁰,--OSiR₃ ¹⁰, --OR¹⁰, --SiR₃ ¹⁰ or --PR₂ ¹⁰ radical, where R¹⁰ is ahalogen atom, preferably a chlorine atom, or a C₁ -C₁₀ -, preferably C₁-C₃ -alkyl group or a C₆ -C₁₀ -, preferably C₆ -C₈ -aryl group,particularly preferably R³ is hydrogen.

The radicals R⁴ are identical or different and are a hydrogen atom, ahalogen atom, a C₁ -C₂₀ -, preferably C₁ -C₁₀ -alkyl group, a C₁ -C₂₀-fluoroalkyl group, preferably C₁ -C₁₀ -fluoroalkyl group, a C₆ -C₃₀ -,preferably C₆ -C₂₀ -aryl group, a C₆ -C₃₀ -fluoroaryl group, preferablya C₆ -C₂₀ fluoroaryl group, a C₁ -C₂₀ -, preferably C₁ -C₁₀ -alkoxygroup, a C₂ -C₂₀ -, preferably C₂ -C₁₀ -alkenyl group, a C₇ -C₄₀ -,preferably C₇ -C₂₀ -arylalkyl group, a C₈ -C₄₀ -, preferably C₈ -C₂₂-arylalkenyl group, a C₇ -C₄₀ -, preferably C₇ -C₂₂ -alkylaryl group, a--NR₂ ¹⁰, --SR¹⁰, --OSiR₃ ¹⁰, --OR¹⁰, --SiR₃ ¹⁰ or --PR₂ ¹⁰ radical,where R¹⁰ is a halogen atom, preferably a chlorine atom, or a C₁ -C₁₀ -,preferably C₁ -C₃ -alkyl group or a C₆ -C₁₀ -, preferably C₆ -C₈ -arylgroup, or two or more radicals R⁴ together with the atoms connectingthem form a ring system which is monocyclic or polycyclic.

R⁵ is a hydrogen atom, a halogen atom, preferably a fluorine, chlorineor bromine atom, a C₁ -C₁₀ -, preferably C₁ -C₄ -alkyl group which canbe halogenated, a C₆ -C₁₀ -, preferably C₆ -C₈ -aryl group, a C₂ -C₁₀ -,preferably C₂ -C₄ -alkenyl group, a C₇ -C₄₀ -, preferably C₇ -C₁₀-arylalkyl group, a C₇ -C₄₀ -, preferably C₇ -C₁₂ -alkylaryl group, a C₈-C₄₀ -, preferably C₈ -C₁₂ -arylalkenyl group, a --NR₂ ¹⁰, --SR¹⁰,--OSiR₃ ¹⁰, --OR¹⁰, --SiR₃ ¹⁰ or --PR₂ ¹⁰ radical, where R¹⁰ is ahalogen atom, preferably a chlorine atom, or a C₁ -C₁₀ -, preferably C₁-C₃ -alkyl group or C₆ -C₁₀ -, preferably C₆ -C₈ -aryl group.

R⁶ is a hydrogen atom, a halogen atom, preferably a fluorine, chlorineor bromine atom, a C₁ -C₂₀ -, preferably C₁ -C₁₀ -alkyl group which canbe halogenated, a C₆ -C₃₀ -, preferably C₆ -C₂₀ -aryl group, a C₂ -C₁₀-, preferably C₂ -C₄ -alkenyl group, a C₇ -C₄₀ -, preferably C₇ -C₁₀-arylalkyl group, a C₇ -C₄₀ -, preferably C₇ -C₁₂ -alkylaryl group, a C₈-C₄₀ -, preferably C₈ -C₁₂ -arylalkenyl group, a --NR₂ ¹⁰, --SR¹⁰,--OSiR₃ ¹⁰, --OR¹⁰, --SiR₃ ¹⁰ or --PR₂ ¹⁰ radical, where R¹⁰ is ahalogen atom, preferably a chlorine atom, or a C₁ -C₁₀ -, preferably C₁-C₃ -alkyl group or a C₆ -C₁₀ -, preferably C₆ -C₈ -aryl group.

R⁷ is ##STR4## ═BR¹¹, ═AlR¹¹, --Ge--, --Sn--,--O--, --S--, ═SO, ═SO₂,═NR¹¹, ═CO, ═PR¹¹ or ═P(O)R¹¹, where R¹¹, R¹² and R¹³ are identical ordifferent and are a hydrogen atom, a halogen atom, a C₁ -C₂₀ -,preferably C₁ -C₁₀ -alkyl group, a C₁ -C₂₀ -fluoroalkyl group,preferably a C₁ -C₁₀ -fluoroalkyl group, a C₆ -C₃₀ -, preferably C₆ -C₂₀-aryl group, a C₆ -C₃₀ - fluoroaryl group, preferably a C₆ -C₂₀-fluoroaryl group, a C₁ -C₂₀ -, preferably C₁ -C₁₀ -alkoxy group, a C₂-C₂₀ -, preferably C₂ -C₁₀ -alkenyl group, a C₇ -C₄₀ -, preferably C₇-C₂₀ -arylalkyl group, a C₈ -C₄₀ -, preferably C₈ -C₂₂ -arylalkenylgroup or a C₇ -C₄₀ -, preferably C₇ -C₂₂ -alkylaryl group, or R¹¹ andR¹² or R¹¹ and R¹³, in each case together with the atoms connectingthem, form a ring.

M¹ is silicon, germanium or tin, preferably silicon or germanium.

R⁷ is preferably ═CR¹¹ R¹², ═SiR¹¹ R¹², ═GeR¹¹ R¹², --O--, --S--, ═SO,═PR¹¹ or ═P(O)R¹¹.

R⁸ and R⁹ are identical or different and are a hydrogen atom, a halogenatom, a C₁ -C₂₀ -, preferably C₁ -C₁₀ -alkyl group, a C₁ -C₂₀-fluoroalkyl group, preferably a C₁ -C₁₀ -fluoroalkyl group, a C₆ -C₃₀-, preferably C₆ -C₂₀ -aryl group, a C₆ -C₃₀ -fluoroaryl group,preferably a C₆ -C₂₀ -fluoroaryl group, a C₁ -C₂₀ -, preferably C₁ -C₁₀-alkoxy group, a C₂ -C₂₀ -, preferably C₂ -C₁₀ -alkenyl group, a C₇ -C₄₀-, preferably C₇ -C₂₀ -arylalkyl group, a C₈ -C₄₀ -, preferably C₈ -C₂₂-arylalkenyl group or a C₇ -C₄₀ -, preferably C₇ -C₂₂ -alkylaryl group,or R⁸ and R⁹ together with the atoms connecting them form a ring.

m and n are identical or different and are zero, 1 or 2, preferably zeroor 1, where m plus n is zero, 1 or 2, preferably zero or 1.

The cyclopentadienyl ligand preferably has a radical which is nothydrogen at at least one of the positions adjacent to the --(CR⁸ R⁹)_(n)--R⁷ --(CR⁸ R⁹)_(m) -- bridge (2 or 5 position) if the metallocene is tobe used for the preparation of a high-molecular-weight highly isotacticpolyolefin. For the preparation of low-molecular-weight low-isotacticitypolyolefins the cyclopentadienyl ligand is preferably unsubstituted orsubstituted only in the 3 position.

Preferred metallocenes of the formula (I) for preparinghigh-molecular-weight, highly isotactic polyolefins are those for whichin formula (I)

M² is zirconium,

R¹ and R² are identical or different and are methyl or chlorine,

R³ is a hydrogen atom,

R⁴ is a hydrogen atom, a C₁ -C₂₀ -alkyl group or a C₆ -C₃₀ -aryl group,or two or more radicals R⁴ together with the atoms connecting them forma ring system,

R⁵ is a hydrogen atom or a C₁ -C₁₀ -, preferably C₁ -C₄ -alkyl group,

R⁶ is a hydrogen atom, a C₁ -C₁₀ -alkyl group, a C₆ -C₂₀ -aryl group ora radical SiR¹⁰ ₃, where R¹⁰ is a C₁ -C₁₀ -alkyl group,

R⁷ is a radical ##STR5## where R¹¹ and R¹² are identical or differentand are a C₁ -C₂₀ -alkyl group or a C₆ -C₃₀ -aryl group, R⁸ and R⁹ areidentical or different and are a hydrogen atom or a C₁ -C₃₀ -alkylgroup, m plus n is zero or 1, and at least one of the radicals R⁶ andalso at least one of the radicals R⁵ and R⁴ is not hydrogen, inparticular those compounds of the formula (I) in which the indenylligand is substituted in the 2, 2,4, 2,5, 2,6, 2,4,6, 2,4,5, 2,4,5,6 or2,5,6 positions, and the cyclopentadienyl ligand is substituted in the2, 3,5 or 2,3,5 positions, where the substituents are preferably C₁ -C₁₀-alkyl, C₆ -C₂₀ -aryl or SiR¹⁰ ₃ radicals, where R¹⁰ is a C₁ -C₁₀ -alkylgroup.

Preferred metallocenes of the formula (I) for preparinglow-molecular-weight, low-isotacticity polyolefins are those for whichin the formula (I)

M² is zirconium,

R¹ and R² are identical or different and are methyl or chlorine,

R³ is hydrogen,

R⁴ is a hydrogen atom, a C₁ -C₂₀ -alkyl group or a C₆ -C₃₀ -aryl group,or two or more radicals R⁴ together with the atoms connecting them forma ring system,

R⁵ is a hydrogen atom or a C₁ -C₁₀ -, preferably C₁ -C₄ -alkyl group,

R⁶ is a hydrogen atom, a C₁ -C₁₀ -alkyl group, a C₆ -C₂₀ -aryl group ora radical SiR¹⁰ ₃, where R¹⁰ is a C₁ -C₁₀ -alkyl group,

R⁷ is a radical ##STR6## where R¹¹ and R¹² are identical or differentand are a C₁ -C₂₀ -alkyl group or a C₆ -C₃₀ -aryl group, R⁸ and R⁹ areidentical or different and are a hydrogen atom or a C₁ -C₃₀ -alkylgroup, m+n is zero or 1, and at least one of the radicals R⁵ and R⁴ isnot hydrogen, in particular those compounds of the formula (I) in whichthe indenyl radical is substituted in the 2, 2,4, 2,5, 2,6, 2,4,6,2,4,5, 2,4,5,6 or 2,5,6 positions, and the cyclopentadienyl ligand isunsubstituted or substituted only in the 3 position, where thesubstituents are preferably C₁ -C₁₀ -alkyl, C₆ -C₂₀ -aryl or --SiR₁₀ ₃radicals, where R¹⁰ is a C₁ -C₁₀ -alkyl group.

The nomenclature used here for the site of substitution is as follows:

Cyclopentadienyl ligand: Indenyl ligand: ##STR7##

Preferred compounds of the formula (I) for preparinghigh-molecular-weight, highly isotactic polymers consist of thefollowing molecular fragments a, b, c and d:

a) --(CR⁸ R⁹)m--R⁷ --(CR⁸ R⁹)_(n) -- is:

dialkylsilanediyl, alkyl(aryl)silanediyl, 1,2-ethanediyl,1,2-butanediyl, diarylsilanediyl, dialkylmethylene, diarylmethylene,alkyl (aryl) methylene, alkyl(vinyl)silanediyl, aryl(vinyl)silanediyl ordialkylgermyl;

b) R⁴ ₄ R³ R⁵ -1-indenyl is:

2-alkyl-4-aryl-1-indenyl, 2,4-dialkyl-1-indenyl, 2,4-diaryl-1-indenyl,2,4,6-trialkyl-1-indenyl, 2-alkyl-α-acenaphth-1-indenyl,2-alkyl-4,5-benzo-1-indenyl, 2,5-dialkyl-1-indenyl,2,6-dialkyl-1-indenyl, 2,5,6-trialkyl-1-indenyl,2,4,5-trialkyl-1-indenyl, 2-alkyl-1-indenyl, 2-aryl-1-indenyl,2,6-dialkyl-4-aryl-1-indenyl, 2-alkyl-5-aryl-1-indenyl,2-alkyl-5,6-diaryl-1-indenyl, 2-alkyl-4,5-diaryl-1-indenyl or2-alkyl-4,6-diaryl-1-indenyl;

c) R⁶ ₃ R³ -1-cyclopentadienyl is:

2-alkyl-1-cyclopentadienyl, 3,5-dialkyl-1-cyclopentadienyl,2,3,5-trialkyl-1-cyclopentadienyl, 2-Si(trialkyl)-1-cyclopentadienyl,5-Si(trialkyl)-3-alkyl-1-cyclopentadienyl,2-Si(trialkyl)-3,5-dialkyl-1-cyclopentadienyl,5-alkyl-3-aryl-1-cyclopentadienyl,2,5-dialkyl-3-aryl-1-cyclopentadienyl,2,3-dialkyl-5-aryl-1-cyclopentadienyl, 2-aryl-1-cyclopentadienyl,5-aryl-3-alkyl-1-cyclopentadienyl, 5-aryl-2,3-dialkyl-1-cyclopentadienylor 5-alkyl-2,3-diaryl-1-cyclopentadienyl;

d) ═MR¹ R² is: ═ZrCl₂, ═ZrClCH₃ or ═Zr(CH₃)₂.

Preferred compounds of the formula (I) for preparinglow-molecular-weight, low-isotacticity polymers consist of the followingmolecule fragments a, b, c and d:

a) --(CR⁸ R⁹)m--R⁷ --(CR⁸ R⁹)_(n) -- is:

dialkylsilanediyl, alkyl(aryl)silanediyl, 1,2-ethanediyl, 1,2-butanediyl, diarylsilanediyl, dialkylmethylene, diarylmethylene,alkyl(aryl)methylene, alkyl(vinyl)silanediyl, aryl(vinyl)silanediyl ordialkylgermyl,

b) R⁴ ₄ R³ R⁵ -1-indenyl is:

2-alkyl-4-aryl-1-indenyl, 2,4-dialkyl-1-indenyl, 2,4-diaryl-1-indenyl,2,4,6-trialkyl-1-indenyl, 2-alkyl-α-acenaphth-1-indenyl,2-alkyl-4,5-benzo-1-indenyl, 2,5-dialkyl-1-indenyl, 2,6-dialkyl-1-indenyl, 2,5,6-trialkyl-1-indenyl, 2,4,5-trialkyl-1-indenyl,2-alkyl-1-indenyl, 2-aryl-1-indenyl, 2,6-dialkyl -4-aryl-1-indenyl,2-alkyl-5-aryl-1-indenyl, 2-alkyl-5,6-diaryl-1-indenyl,2-alkyl-4,5-diaryl-1-indenyl or 2-alkyl-4,6-diaryl-1-indenyl;

c) R⁶ ₃ R³ -1-cyclopentadienyl is:

3-alkyl-1-cyclopentadienyl, 3-aryl-1-cyclopentadienyl, or1-cyclopentadienyl;

d) ═MR¹ R² is: ═ZrCl₂, ═ZrClCH₃ or ═Zr(CH₃)₂.

Examples of compounds of the formula (I) which are particularly suitablefor preparing high-molecular-weight, highly isotactic polymers are:

dimethylsilanediyl(2-methyl-4-phenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,

dimethylsilanediyl(2-methyl-4-phenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrMeCl,

dimethylsilanediyl(2-methyl-4-phenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrMe₂,

dimethylsilanediyl(2-methyl-4-phenyl-1-indenyl)(2-methyl-1-cyclopentadienyl)ZrCl₂,

dimethylsilanediyl(2-methyl-4-phenyl-1-indenyl)(3,5-dimethyl-1-cyclopentadienyl)ZrCl₂,

dimethylsilanediyl(2-methyl-4-phenyl-1-indenyl)(2,5-dimethyl-3-t-butyl-1-cyclopentadienyl)ZrCl₂,

1,2-ethanediyl(2-methyl-4-phenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,

phenyl(methyl)silanediyl(2-methyl-4-phenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,

diphenylsilanediyl(2-methyl-4-phenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,

dimethylsilanediyl(2-ethyl-4-phenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,

dimethylsilanediyl(2,4-diphenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,

dimethylsilanediyl(2-ethyl-4-(1-naphthyl)-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,

dimethylgermyl(2-methyl-4-phenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,

methyl(vinyl)silanediyl(2-methyl-4-phenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,

phenyl(vinyl)silanediyl(2-methyl-4-phenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,

dimethylgermyl(2-ethyl-4-(1-naphthyl)-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,

dimethylsilanediyl(2-methyl-4-(1-naphthyl)-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,

dimethylsilanediyl(2-methyl-4-(2-naphthyl)-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,

dimethylsilanediyl(2-methyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,

dimethylsilanediyl(2-methyl-4-isopropyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,

dimethylsilanediyl(2-methyl-4,5-benzo-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,

dimethylsilanediyl(2-methyl-α-acenaphth-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,

dimethylsilanediyl(2-methyl-4,6-diisopropyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,

dimethylsilanediyl(2,4,6-trimethyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,

dimethylsilanediyl(2,5,6-trimethyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,

dimethylsilanediyl(2,4,5-trimethyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,

dimethylsilanediyl(2,5-dimethyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂and

dimethylsilanediyl(2,6-dimethyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂.

Examples of the compounds of the formula (I) which are particularlysuitable for preparing low-molecular-weight, low-isotacticity polymersare:

dimethylsilanediyl(2-methyl-4,5-benzo-1-indenyl)(3-methyl-1-cyclopentadienyl)ZrCl₂,

dimethylmethylene(2-methyl-1-indenyl)(cyclopentadienyl) ZrCl₂,

dimethylmethylene(4,5-benzo-1-indenyl)(cyclopentadienyl) ZrCl₂,

dimethylgermyl(4,5-benzo-1-indenyl)(cyclopentadienyl) ZrCl₂,

dimethylsilanediyl(2-methyl-4,5-benzo-1-indenyl)(cyclopentadienyl)ZrCl.sub.2,

dimethylsilanediyl(2-methyl-4-phenyl-1-indenyl)(3-methyl-1-cyclopentadienyl)ZrCl₂,

dimethylgermyl(2-methyl-4-phenyl-1-indenyl)(cyclopentadienyl)ZrCl₂,

dimethylsilanediyl(4-phenyl-1-indenyl)(3-methyl-1-cyclopentadienyl)ZrCl.sub.2,

dimethylsilanediyl(4-phenyl-1-indenyl)(cyclopentadienyl)ZrCl₂,

dimethylmethylene(4-phenyl-1-indenyl)(cyclopentadienyl) ZrCl₂ and

dimethylsilanediyl(4,5-benzo-1-indenyl)(cyclopentadienyl) ZrCl₂.

The metallocenes of the formula (I) can in principle be preparedaccording to the following reaction scheme: ##STR8## (cf. Journal ofOrganomet. Chem. (1985) 63-67 and EP-A 320 762)

The present invention also provides a process for preparing an olefinpolymer by polymerization of at least one olefin in the presence of acatalyst which contains at least one metallocene as transition metalcompound and at least one cocatalyst, wherein the metallocene is acompound of the formula I.

The polymerization can be a homopolymerization or a copolymerization.Preference is given to homopolymerizing or copolymerizing olefins of theformula R^(a) --CH═CH--R^(b), where R^(a) and R^(b) are identical ordifferent and are a hydrogen atom or a hydrocarbon radical having from 1to 20 carbon atoms, in particular from 1 to 10 carbon atoms, or R^(a)and R^(b) together with the atoms connecting them form one or morerings. Examples of such olefins are 1-olefins such as ethylene,propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene or1-octene, styrene, dienes such as 1,3-butadiene or 1,4-hexadiene andcyclic olefins such as norbornene, tetracyclododecene, norbornadiene orvinylnorbornene.

In the process of the invention, preference is given to homopolymerizingethylene or propylene, or copolymerizing ethylene with one or more1-olefins having 3-20 carbon atoms, such as propylene, and/or one ormore dienes having 4-20 carbon atoms, such as 1,3-butadiene. Examples ofcopolymers are ethylene/propylene copolymers,ethylene/propylene/1,4-hexadiene copolymers,ethylene/propylene/5-ethylidene-2-norbornene copolymers orethylene/norbornene copolymers.

The process of the invention is particularly suitable for preparingisotactic olefin polymers.

The polymerization is preferably carried out at a temperature of from 0°to 200° C., particularly preferably from 50° to 100° C. The pressure ispreferably from 0.5 to 100 bar, in particular from 5 to 64 bar.

The polymerization can be carried out in solution, in suspension or inthe gas phase, continuously or batchwise, and in one or more stages.

The catalyst used in the process of the invention preferably containsone metallocene and one cocatalyst. It is also possible to use mixturesof two or more metallocenes of the invention, in particular forpreparing polyolefins having a broad or multimodal molecular weightdistribution.

In principle, the cocatalyst in the process of the invention can be anycompound which, owing to its Lewis acidity, can convert the neutralmetallocene into a cation and stabilize the latter ("labilecoordination"). Furthermore, the cocatalyst or the anion formedtherefrom should undergo no further reactions with the metallocenecation formed (EP 427 697). Cocatalyst used are preferably aluminumand/or boron compounds.

As aluminum compound, preference is given in the process of theinvention to using an aluminoxane which preferably has the formula II##STR9## for the linear type and/or the formula III ##STR10## for thecyclic type, where, in the formulae II and III, the radicals R¹⁴ can beidentical or different and are a C₁ -C₆ -alkyl group, a C₁ -C₆-fluoroalkyl group, a C₆ -C₁₈ -aryl group, a C₆ -C₁₈ -fluoroaryl groupor hydrogen and n is an integer from 0 to 50, or in place of thealuminoxane a mixture of an aluminoxane with a compound AlR₃ ¹⁵, whereR¹⁵ is as defined for R¹⁴.

Preferably, the radicals R¹⁴ are identical and are methyl, isobutyl,phenyl or benzyl, particularly preferably methyl.

If the radicals R¹⁴ are different, then they are preferably methyl andhydrogen or alternatively methyl and isobutyl, where hydrogen orisobutyl are preferably present in an amount of 0.01-40% (radicals R¹⁴).The cocatalyst in the polymerization can be, in place of thealuminoxane, a mixture consisting of aluminoxane and AlR₃ ¹⁵, where R¹⁵is as defined for R¹⁴. Preferably, the radicals R¹⁵ are identical andare methyl, ethyl, isobutyl, phenyl or benzyl.

The aluminoxane can be prepared in various ways by known methods. One ofthe methods is, for example, reacting an aluminum-hydrocarbon compoundand/or a hydridoaluminum-hydrocarbon compound with water (gaseous,solid, liquid or bound, for example as water of crystallization) in aninert solvent (such as toluene). To prepare an aluminoxane havingdiffering alkyl groups R¹⁴, two different aluminumtrialkyls (AlR¹⁴ ₃+AlR¹⁴ ₃) corresponding to the desired composition are reacted withwater (cf. S. Pasynkiewicz, Polyhedron 9 (1990) 429 and EP-A 302 424).

The exact three-dimensional structure of the aluminoxanes is not known(A. R. Barron et al., J. Am. Chem. Soc. 115 (1993) 4971). For example,it is conceivable that chains or rings join to form largertwo-dimensional or three-dimensional structures.

Independently of the method of preparation, all aluminoxane solutionshave in common a varying content of unreacted aluminum starting compoundwhich is present in free form or as an adduct.

It is possible to preactivate the metallocenes with a cocatalyst, inparticular aluminoxane, prior to use in the polymerization reaction.This significantly increases the polymerization activity and improvesthe particle morphology.

The preactivation of the metallocenes is carried out in solution.Preference is here given to dissolving the solid metallocenes in asolution of the aluminoxane in an inert hydrocarbon. Suitable inerthydrocarbons are aliphatic or aromatic hydrocarbons. Preference is givento using toluene or a C₆ -C₁₀ -hydrocarbon.

The concentration of the aluminoxane in the solution is preferably inthe range from about 1% by weight to the saturation limit, preferablyfrom 5 to 30% by weight, in each case based on the total solution. Themetallocenes can be used in the same concentration, but they arepreferably used in an amount of 10⁻⁴ -1 mole per mole of aluminoxane.The preactivation time is from 1 minute to 60 hours, preferably from 2to 60 minutes. It is carried out at a temperature of from -78° C. to100° C., preferably from 0° to 70°C.

The metallocene can (if desired together with a cocatalyst) be appliedto a support and/or be prepolymerized. For the prepolymerization,preference is given to using the (or one of the) olefin(s) used in thepolymerization.

Suitable supports are, for example, silica gels, aluminum oxides, solidaluminoxane, combinations of aluminoxane on a support such as, forexample, silica gel, or other inorganic support materials. Anothersuitable support material is a polyolefin powder in finely divided form.

A further possible embodiment of the process of the invention comprisesusing a salt-like boron compound of the formula R_(x) NH_(4-x) BR'₄ orthe formula R₃ PHBR'₄ as cocatalyst in place of or in addition to analuminoxane. Here x=1, 2 or 3, R=alkyl or aryl, identical or different,and R'=aryl which can also be fluorinated or partially fluorinated. Inthis case, the catalyst consists of the reaction product of themetallocenes with one of the specified compounds (cf. EP-A 277 004).

To remove catalyst poisons present in the olefin, a purification usingan aluminumalkyl, for example AlMe₃ or AlEt₃ is advantageous. Thispurification can either be carried out in the polymerization systemitself, or the olefin is, prior to addition to the polymerizationsystem, brought into contact with the aluminum compound and subsequentlyseparated off again.

The addition of hydrogen effects an additional strong increase in thepolymerization activity.

The total pressure in the polymerization system is from 0.5 to 100 bar.The polymerization is preferably carried out in the industriallyparticularly important pressure range from 5 to 64 bar.

The metallocenes are preferably used in a concentration, based on thetransition metal, of from 10⁻³ to 10⁻⁸ mol, preferably from 10⁻⁴ to 10⁻⁷mol, of transition metal per dm³ of solvent or per dm³ of reactorvolume. The cocatalyst, such as aluminoxane or an aluminoxane/AIR¹¹ ₃mixture, is preferably used in a concentration of from 10⁻⁵ to 10⁻¹ mol,preferably from 10⁻⁴ to 10⁻² mol, per dm³ of solvent or per dm³ ofreactor volume. However, higher concentrations are also possible inprinciple.

If the polymerization is carried out as a suspension or solutionpolymerization, an inert solvent customary for the Ziegler low-pressureprocess is used. For example, the polymerization is carried out in analiphatic or cycloaliphatic hydrocarbon; examples which may be mentionedbeing propane, butane, pentane, hexane, heptane, decane, isooctane,cyclohexane, methylcyclohexane.

Furthermore, it is possible to use a gasoline or hydrogenated diesel oilfraction. Toluene can also be used. Preferably, polymerization iscarried out in the liquid monomer.

If inert solvents are used, the monomers are metered in gaseous orliquid form.

The duration of the polymerization is as desired, since the catalystsystem of the invention shows only a small time-dependent decrease inthe polymerization activity.

The process of the invention can, in particular in the industriallyimportant temperature range from 50° to 100° C., be used to preparepolyolefins having a high molecular weight and a high isotacticity.These are important, in particular, for the preparation of shaped partssuch as films, plates or large hollow bodies (e.g. pipes).

The process of the invention can also be used to prepare polyolefinshaving a low molecular weight and a low isotacticity, as are importantfor coatings and adhesive applications.

The metallocene of the invention has a high catalyst activity, inparticular at temperatures between 50° and 100° C. In addition, thecomplicated separation of the meso form becomes superfluous.Furthermore, combination of different ligands provides metalloceneswhich give isotactic polyolefins having tailored properties.

In particular, the metallocenes of the invention in supported form givepolyolefins having very good powder morphologies.

The following examples are intended to illustrate the invention ingreater detail.

Definitions:

VN=Viscosity number in cm³ /g

M_(W) =Weight-average molecular weight in g/mol determined by GPC)

M_(w) /M_(n) =Polydispersity (determined by GPC)

II=Isotactic index (mm+1/2 mr) (determined by ¹³ C-NMR)

n_(iso) =Isotactic block length (determined by ¹³ C-NMR)

MFI (230/2.16) Melt flow index determined in accordance with DIN 53735in dg/min

MFI (230/5) Melt flow index determined in accordance with DIN 53735 indg/min

m.p.=Melting point determined by DSC in ° C. (20° C./min heating andcooling rate)

rac=The structural unit formed by the central atom and the two ligandshas approximately C_(s) symmetry (the fused 6-membered ring of theindenyl ligand is not taken into account in considering the symmetry).

pseudo-rac=The structural unit formed by the central atom and the twoligands has approximately C₂ symmetry (the fused 6-membered ring of theindenyl ligand is not taken into account in considering the symmetry).

Rac and pseudo-rac compounds are chiral at the central atom.

All glass apparatus was baked out in vacuo and flushed with argon. Alloperations were carried out with exclusion of moisture and oxygen inSchlenk vessels. The solvents used were, with the exception ofdichloromethane, distilled under argon from a Na/K alloy.Dichloromethane was distilled under argon from CaH₂.

Example 1Dimethylsilanediyl(2-methyl-4-phenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)zirconiumdichloride (1)

29 ml of a 2.5M solution of butyllithium in hexane were added dropwiseat room temperature to a solution of 15 g (73 mmol) of2-methyl-7-phenylindene in 150 ml of toluene and 7.5 ml of Et₂ O over aperiod of 30 minutes and the mixture was subsequently stirred for 2hours at 40° C. The suspension was subsequently added dropwise at roomtemperature to a solution of 35.3 ml (290 mmol) ofdimethyldichlorosilane in 100 ml of toluene and the mixture was stirredfor a further 3 hours at room temperature. The solvent was removed invacuo and the residue was dried in vacuo (0.1 torr) and subsequentlytaken up in 200 ml of toluene. To this solution was added dropwise, atroom temperature, a suspension of 1,2,4-trimethylcyclopentadienyllithium(prepared by reaction of 7.9 g (73 mmol) of1,2,4-trimethylcyclopentadiene in 60 ml of toluene and 6 ml of THF atroom temperature with 29 ml of a 2.5M solution of butyllithium in hexaneand stirring further for 1 hour at 40° C.) over a period of 50 minutesand the mixture was subsequently stirred for a further 2 hours at roomtemperature. The reaction mixture was admixed with 100 ml of water, thephases were separated and the organic phase was washed with 50 ml ofwater. The solvents were removed in vacuo and the residue was purifiedby chromatography on 400 g of silica gel (hexane/methylene chloride9:1). This gave 10.3 g (38%) of the ligand system of compound 1 as acolorless oil.

27 ml (74 mmol) of a 20% strength solution of butyllithium in toluenewas added dropwise at 50° C. to a solution of 10.0 g (37 mmol) of theligand system of compound 1 in 50 ml of toluene over a period of 20minutes and the mixture was subsequently stirred for a further 2 hoursat 100° C. After gas evolution had ceased, the mixture was cooled to-40° C. and admixed with 8.6 g (37 mmol) of ZrCl₄ and stirred for afurther 1 hour at room temperature. It was again cooled to -40° C.,admixed with 5 ml of THF and filtered through a G3 Schlenk frit.

The filtrate was evaporated to half its volume and allowed tocrystallize at -30° C. The precipitated solid was filtered off, washedthree times with 20 ml of hexane each time and subsequently dried. Thisgave 9 g (46%) of compound (1) as a yellow solid.

¹ H-NMR (100 MHz, CDCl₃): 6.9-7.8 (m, 8H, arom. H and β-H-Ind), 6.4 (s,1H, H-Cp), 1.9-2.1 (4s, 16H, CH₃), 1.0 and 1.1 (2s, 6H, CH₃ Si).

Mass spectrum. 530 M⁺, correct disintegration pattern.

Example 2

Dimethylsilanediyl(2-methyl-4,5-benzoindenyl)(cyclopentadienyl)zirconium dichloride (2)

111 ml of a 2.5M solution of butyllithium hexane were added dropwise atroom temperature to a solution of 50.1 g (278 mmol) of2-methyl-4,5-benzoindene (the preparation is described in EP 549 900) in500 ml of toluene and 25 ml of Et₂ O over a period of 30 minutes and themixture was subsequently stirred for a further 2 hours at 40° C. Thesuspension was subsequently added dropwise at room temperature to asolution of 135 ml (1112 mmol) of dimethyl dichlorosilane in 200 ml oftoluene and the mixture was stirred for a further 3 hours at roomtemperature. The solvent was removed in vacuo, the residue was dried invacuo (0.1 torr) and subsequently taken up in 200 ml of toluene. Thesuspension is filtered off from lithium chloride and the solvent of thefiltrate is removed in vacuo. This gives 43 g (57%) of a red oilyproduct.

17.6 g (64.7 mmol) of dimethyl(2-methyl-4,5-benzoindenyl)chlorosilanewere initially charged in 100 ml of THF and a suspension ofcyclopentadienyllithium (prepared by reaction of 6.4 g (97.6mmol) ofcyclopentadiene in 50 ml of THF with 39.0 ml (97.6 mmol) of a 2.5Msolution of butyllithiumin hexane and stirring further for 1 hour at 40°C.) was added dropwise at room temperature over a period of 15 minutesand the mixture was subsequently stirred for a further 2 hours at roomtemperature. The reaction mixture was admixed with 250 ml of water, thephases were separated and the organic phase was washed with 50 ml ofwater. The solvents were removed in vacuo and the residue was purifiedby chromatography on 400 g of silica gel (hexane/methylene chloride10:1). This gave 10.37 g (53%) of the ligand system of compound (2) as acolorless oil.

7.3 ml (18.3 mmol) of a solution of butyllithium in hexane (2.5M) wereadded dropwise at room temperature to a solution of 2.64 g (8.7 mmol) ofthe ligand system of compound 2 in 50 ml of toluene/5 ml of Et₂ O over aperiod of 20 minutes and the mixture was subsequently stirred for afurther 2 hours at room temperature. After gas evolution had ceased, themixture was cooled to -40° C., admixed with 1.98 g (8.5 mmol) of ZrCl₄and stirred for a further 1 hour at room temperature. The suspension wasfiltered through a G3 frit, washed twice with 20 ml of CH₂ Cl₂ and thesolvent removed from the filtrate in vacuo. Recrystallization from CH₂Cl₂ gives 2.39 g (61%) of the metallocene (2).

¹ H-NMR (300 MHz, CDCl₃): δ=8.06 (m, 6H, arom. H); 7.18 (m, 1H,benzoindenyl-H); 6.68 (m, 2H, Cp-H); 5.96 (m, 1H, Cp-H); 5.80 (m, 1H,Cp-H); 2.28 (s, 3H, CH₃ -benzo.-H); 1.03/0.91 (each s, each 3H, (CH₃)₂Si).

Example 3 Isopropylidene(4,5-benzoindenyl)(cyclopentadienyl)zirconiumdichloride (3)

13.8 ml (34.5 mmol) of a 2.5M solution of butyllithium in hexane wereadded dropwise at 0° C. to a solution of 6.2 g (37.3 mmol) of4,5-benzoindene (the preparation is described in DE 4139595) in 55 ml ofTHF over a period of 30 minutes and the mixture was subsequently stirredfor a further 2 hours at 40° C. The suspension was subsequently added at-30° C. to a solution of 3.6 g (34.3 mmol) of 6,6-dimethylfulvene in 16ml of THF. The mixture is allowed slowly to warm up to room temperaturein a cold bath and is stirred for a further 3 hours at room temperature.The suspension was admixed with 100 ml of water, the phases wereseparated and the organic phase was washed with 50 ml of water. Thesolvents were removed in vacuo and the residue was purified bychromatography on 350 g of silica gel (isohexane/diisopropyl ether 1%).This gave 5.1 g (55%) of the ligand system of compound (3) as a yellowoil.

15.7 ml (39.3 mmol) of a solution of butyllithium in hexane (2.5M) wereadded dropwise at room temperature to a solution of 5.1 g (18.7 mmol) ofthe ligand system of compound 3 in 100 ml of Et₂ O and subsequentlystirred for a further 2 hours at room temperature. The suspension isfiltered and gives, after drying in vacuo, 6.4 g (17.9 mmol) of thedilithium compound to which one molecule of ether is coordinated. Thisdilithium compound is added at -78° C. to a suspension of 4.0 g (17.1mmol) of ZrCl₄ in 100 ml of toluene. The mixture is allowed slowly towarm up to room temperature in a cold bath and is stirred for a further1 hour at room temperature. The suspension was filtered through a G4frit and washed twice with 40 ml of toluene. The residue was extractedwith 500 ml of CH₂ Cl₂ and the filtrate was reduced to 50 ml in vacuo.After isolating the yellow solid formed by filtration and subsequentdrying in vacuo, 5.8 g (79%) of the metallocene (3) are obtained as ayellow powder.

¹ H-NMR (100 MHz, CDCl₃): δ=8.18-7.41 (m, 6H, arom. H); 7.22 (m, 1H,benzoindenyl-H); 6.50 (m, 2H, Cp-H); 6.13 (d, 1H, benzoindenyl-H); 5.88(m, 1H, Cp-H); 5.77 (m, 1H, Cp-H); 2.25/1.98 (each s, each 3H, (CH₃)₂C).

Example 4Dimethylsilanediyl(4,5-benzoindenyl)(cyclopentadienyl)zirconiumdichloride (4)

26.7 ml (66.8 mmol) of a 2.5M solution of butyllithium hexane were addeddropwise at 0° C. to a solution of 11.1 g (66.8 mmol) of 4,5-benzoindenein 120 ml of toluene and 6 ml of Et₂ O over a period of 30 minutes andsubsequently stirred for a further 2 hours at 40° C. The suspension wassubsequently added dropwise at room temperature to a solution of 32.4 ml(267 mmol) of dimethyldichlorosilane in 200 ml of toluene and themixture was stirred for a further 3 hours at room temperature. Thesuspension is filtered off from the lithium chloride and the solvent ofthe filtrate is removed in vacuo. This gives 16.8 g (97%) of a yellowoily product.

16.8 g (64.7 mmol) of dimethyl(4,5-benzoindenyl)chlorosilane wereinitially charged in 80 ml of THF, admixed at room temperature with asolution of 8.5 g (96.5 mmol) of cyclopentadienylsodium in 80 ml of THFand the mixture was subsequently stirred for a further 2 hours at roomtemperature. The reaction mixture was admixed with 300 ml of water, thephases were separated and the organic phase was washed with 50 ml ofwater. The solvents were removed in vacuo and the residue was purifiedby chromatography on 400 g of silica gel (iso-hexane/diisopropyl ether2%). This gave 14.3 g (77%) of the ligand system of compound 4 as a paleyellow oil.

22.9 ml (58.2 mmol) of a solution of butyllithium in hexane (2.5M) wereadded dropwise at room temperature to a solution of 8.0 g (27.7 mmol) ofthe ligand system of compound 4 in 200 ml of Et₂ O and subsequentlystirred for a further 2 hours at room temperature. The suspension wasfiltered and, after drying in vacuo, gives 9.0 g (24 mmol) of thedilithium compound to which one molecule of ether is coordinated. Thisdilithium compound is added at -78° C. to a suspension of 5.3 g (22.8mmol) of ZrCl₄ in 140 ml of toluene. The mixture is allowed slowly towarm up to room temperature in a cold bath and is stirred for a furtherone hour at room temperature. The suspension was filtered through a G4frit and washed twice with 25 ml of toluene. The residue was extractedwith 500 ml of CH₂ Cl₂ and the filtrate was reduced to 50 ml in vacuo.After isolating the yellow solid formed by filtration and subsequentdrying in vacuo, 6.3 g (62%) of the metallocene (4) are obtained.

¹ H-NMR (100 MHz, CDCl₃): δ=8.10-7.25 (m, 6H, arom. H); 7.41 (m, 1H,benzoindenyl-H); 6.75 (m, 2H, Cp-H); 6.20 (d, 1H, benzoindenyl-H); 5.94(m, 2H, Cp-H); 1.04/0.88 (each s, each 3H, (CH₃)₂ Si).

Example 5 Isopropylidene(2-methylindenyl)(cyclopentadienyl)zirconiumdichloride (5)

6.2 ml (15.4mmol) of a 2.5M solution of butyllithium in hexane wereadded dropwise at 0° C. to a solution of 2.0 g (15.4 mmol) of2-methylindene in 20 ml of THF over a period of 5 minutes andsubsequently stirred for a further 2 hours at 40° C. The suspension wassubsequently added at -30° C. to a solution of 1.6 g (15.4mmol) of6,6-dimethylfulvene in 10 ml of THF. The mixture is allowed slowly towarm up to room temperature in a cold bath and is stirred for a further3 hours at room temperature. The suspension was admixed with 100 ml ofwater, the phases were separated and the organic phase was washed with50 ml of water. The solvents were removed in vacuo and the residue waspurified by chromatography on silica gel (iso-hexane/diisopropyl ether1%). This gave 3.2 g (88%) of the ligand system of compound 5 as ayellow oil.

11.4 ml (28.4 mmol) of a solution of butyllithium in hexane (2.5M) wereadded dropwise at room temperature to a solution of 3.2 g (13.5 mmol) ofthe ligand system of compound 5 in 90 ml of Et₂ O and subsequentlystirred for a further 2 hours at room temperature. The suspension isfiltered and, after drying in vacuo, gives 4.0 g (12.4 mmol) of thedilithium compound to which one molecule of ether is coordinated. Thisdilithium compound is added at -78° C. to a suspension of 2.7 g (11.8mmol) of ZrCl₄ in 65 ml of toluene. The mixture is allowed slowly towarm up to room temperature in a cold bath and is stirred for a further1 hour at room temperature. The yellow suspension was filtered through aG4 frit and washed twice with 10 ml of toluene. The residue wasextracted with 120 ml of CH₂ Cl₂ and the filtrate was reduced to 15 mlin vacuo. After isolating the resultant yellow solid by filtration andsubsequent drying in vacuo, 4.02 g (86%) of the metallocene (5) areobtained as a yellow powder.

¹ H-NMR (100 MHz, CDCl₃): δ=7.80-6.85 (m, 4H, arom. H); 6.62 (s, 1H,indenyl-H); 6.50 (m, 2H, Cp-H); 5.80 (m, 2H, Cp-H); 2.37/2.23/2.12 (eachs, each 3H, (CH₃)₂ C or CH₃ -Ind.).

Example 6

Dimethylsilanediyl(2-methyl-4,5-benzoindenyl)(2-methylcyclopentadienyl)zirconiumdichloride (6)

111 ml of a 2.5M solution of butyllithiumin hexane were added dropwiseat room temperature to a solution of 50.1 g (278 mmol) of2-methyl-4,5-benzoindene (the preparation is described in EP 549 900) in500 ml of toluene and 25 ml of Et₂ O over a period of 30 minutes andsubsequently stirred for a further 2 hours at 40° C. The suspension wassubsequently added dropwise at room temperature to a solution of 135 ml(1112 mmol) of dimethyldichlorosilane in 200 ml of toluene and themixture was stirred for a further 3 hours at room temperature. Thesolvent was removed in vacuo, the residue was dried in vacuo (0.1 torr)and subsequently taken up in 200 ml of toluene. The suspension isfiltered off from lithium chloride and the solvent of the filtrate isremoved in vacuo. This gives 43 g (57%) of a red oily product.

15.0 g (55 mmol) of dimethyl(2-methyl-4,5-benzoindenyl)chlorosilane wereinitially charged in 70 ml of THF and a suspension ofmethylcyclopentadienyllithium (prepared by reaction of 4.85 g (60.5mmol) of methylcyclopentadiene in 60 ml of THF with 24.2 ml (60.5mmol)of a 2.5M solution of butyllithium in hexane and further stirring for 1hour at 40° C.) was added dropwise over a period of 15 minutes and themixture was subsequently stirred for a further 4 hours at roomtemperature. The reaction mixture was admixed with 250 ml of water, thephases were separated and the organic phase was washed with 50 ml ofwater. The solvents were removed in vacuo and the residue was purifiedby chromatography on 400 g of silica gel (hexane/2% ethyl acetate). Thisgave 9.92 g (57%) of the ligand system of compound 6 as a colorless oil.

13.2 ml (33.2 mmol) of a 2.5M solution of butyllithium in hexane wereadded dropwise at room temperature to a solution of 5.0 g (15.8 mmol) ofthe ligand system of compound 6 in 90 ml of diethyl ether over a periodof 20 minutes and subsequently stirred for a further 2 hours at roomtemperature. The solvent was removed in vacuo and the oily residue wasstirred with pentane. The solid formed is filtered off and dried invacuo. This gives 4.89 g of lithium salt to which i equivalent of etheris still coordinated. 3.49 g (15 mmol) of ZrCl₄ are initially charged in100 ml of methylene chloride at -78° C. and admixed with the lithiumsalt. The mixture is allowed to warm up to room temperature over aperiod of 12 hours and is stirred for a further 1 hour at roomtemperature. The suspension was filtered through a G3 frit, washed twicewith 20 ml of methylene chloride and the residue on the frit was driedin vacuo. This gives 2.22 g (31%) of the rac compound (6).

¹ H-NMR (100 MHz, CDCl₃): δ=8.27-7.04 (m, 8H, arom. H andbenzoindenyl-H), 6.80-5.40 (m, 3H, Cp-H), 2.32/2.04 (each s, each 3H,CH₃ -Cp and CH₃ -benzo.); 1.04/0.94 (each s, each 3H, (CH₃)₂ Si).

The filtrate was evaporated to 1/5 of its volume and was kept at -30° C.until it crystallized. This gave 1.81 g of the "pseudo-rac" complex (6)as a yellow solid.

¹ H-NMR (100 MHz, CDCl₃): δ8.10-7.14 (m, 8H, arom. H andbenzoindenyl-H), 6.53-5.51 (m, 3H, Cp-H), 2.29/2.25 (each s, each 3H,CH₃ -Cp and CH₃ -benzo.); 1.10/0.89 (each s, each 3H, (CH₃)₂ Si).

Polymerization Examples Example A

A dry 24 dm³ reactor was flushed with propylene and charged with 12 dm³of liquid propylene and 25 cm³ of methylaluminoxane solution in toluene(corresponding to 37 mmol of Al, average degree of oligomerization wasn=20). The contents were stirred at 30° C. for 5 minutes at 250 rpm. Inparallel thereto, 2.0 mg ofdimethylsilanediyl(2-methyl-4-phenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)zirconiumdichloride (1) were dissolved in 10 cm³ of methylaluminoxane solution intoluene (17 mmol of Al) and preactivated by being left to stand for 5minutes. The solution was added to the reactor and polymerization wascarried out for 1 hour at 70° C. This gave 1.27 kg of polypropylene. Themetallocene activity was 635 kg PP/g metallocene×h. The followingproperties were determined on the polymer:

VN=275 cm³ /g; M_(w) =385 500 g/mol; M_(w) /M_(n) =2.05; MFI (230/2)=3.9dg/min; m.p. 157° C.; II=98.0%; n_(iso) =98.

Example B

Example A was repeated at a polymerization temperature of 50° C. Themetallocene activity was 265 kg PP/g metallocene×h.

VN=485 cm³ /g; M_(w) =564,000 g/mol; M_(w) /M_(n) =2.1; MFI (230/5)=0.9dg/min; m.p. 162° C.; II=98.9%; n_(iso) =150.

Example C (Comparative Example)

Example A was repeated using the metalloceneracdimethylsilanediylbis(2,3,5-trimethyl-1-cyclopentadienyl)zirconiumdichloride. The activity achieved was 85 kg PP/g metallocene×h and thepolymer had the following properties:

VN=53 cm³ /g; M_(w) =46,100 g/mol; M_(w) /M_(n) =2.8; MFI notmeasurable, since polymer was too fluid; m.p. 152° C.; II=97.0%.

Examples D to H

A dry 1.5 dm³ reactor was flushed with nitrogen and charged at 20° C.with 0.75 dm³ of a de-aromatized petroleum fraction having a boilingrange from 100° to 120° C. The gas space of the reactor was then flushedfree of nitrogen by pressurizing with 2 bar of ethylene anddepressurizing 5 times. 3.75 cm³ of methylaluminoxane solution intoluene (5 mmol of Al , n=18) were then added. While stirring, thereactor was heated to 30° C. (over a period of 15 minutes) and, at astirring speed of 500 rpm, a total pressure of 5 bar was set by additionof ethylene. In parallel thereto, 0.125 mg of metallocene (for type ofcompound, see Table 1) was dissolved in 1.25 cm³ of methylaluminoxanesolution in toluene (1.67 mmol of Al, n=18) and was completely reactedby being left to stand for 15 minutes. The solution was then added tothe reactor, the polymerization system was brought to 70° C. and, bymeans of appropriate cooling, was left at this temperature for 1 hour.During this time, the pressure was maintained at 5 bar by appropriateaddition of ethylene. The polymerization was then stopped by addition of2 ml of isopropanol, the polymer was filtered off and dried in vacuo.The results of the polymerizations are shown in Table 1.

                                      TABLE 1                                     __________________________________________________________________________    Ethylene Polymerizations (Examples D to H)                                                                      Activity  VN                                Example                                                                            Metallocene                  [kg PE/g met. × h]                                                                [cm.sup.3 /g]                     __________________________________________________________________________    D    Me.sub.2 Si (4,5-benzo-1-indenyl) (methylcyclopentadienyl)                    ZrCl.sub.2                   98        149                               E    Me.sub.2 Si (4,5-benzo-1-indenyl) (cyclopentadienyl)                                                       120l.sub.2                                                                              162                               F    Me.sub.2 C (4,5-benzo-1-indenyl) (cyclopentadienyl)                                                        14Cl.sub.2                                                                              59                                G    Me.sub.2 Si (2-me-4,5-benzo-1-indenyl) (cyclopentadienyl)                                                  66Cl.sub.2                                                                              340                               H    Me.sub.2 C (2-me-1-indenyl) (cyclopentadienyl) ZrCl.sub.2                                                  20        75                                __________________________________________________________________________

Examples I to M

Example A was repeated at a polymerization temperature of 60° C., butusing the metallocenes listed in Table 2. The results of thepolymerizations are likewise shown in Table 2.

                                      TABLE 2                                     __________________________________________________________________________    Propylene Polymerizations (Examples I to M)                                                                     Activity  VN                                Example                                                                            Metallocene                  [kg PE/g met. × h]                                                                [cm.sup.3 /g]                     __________________________________________________________________________    I    Me.sub.2 Si (4,5-benzo-1-indenyl) (methylcyclopentadienyl)                    ZrCl.sub.2                   97        62                                J    Me.sub.2 Si (4,5-benzo-1-indenyl) (cyclopentadienyl)                                                       57Cl.sub.2                                                                              20                                K    Me.sub.2 C (4,5-benzo-1-indenyl) (cyclopentadienyl)                                                        17Cl.sub.2                                                                              8                                 L    Me.sub.2 Si (2-me-4,5-benzo-1-indenyl) (cyclopentadienyl)                                                  360l.sub.2                                                                              34                                M    Me.sub.2 C (2-me-1-indenyl) (cyclopentadienyl) ZrCl.sub.2                                                  36        10                                __________________________________________________________________________

Example N

Example A was repeated, but an additional 3 standard dm³ of hydrogenwere introduced into the reactor prior to addition of the propylene.

The metallocene activity was 964 kg PP/g metallocene×h. The followingproperties were determined on the polymer:

VN=128 cm³ /g; M_(w) =171,500 g/mol; M_(w) /M_(n) =1.9; MFI (230/2)=83dg/min; m.p. 158° C.

Example O

Example A was repeated, but the polymerization temperature was 50° C.and during the polymerization time 50 g of ethylene were metered intothe reactor (0.8 g ethylene/min metering rate). This gave 1.17 kg ofrandom copolymer. The metallocene activity was 585 kg copolymer/gmetallocene×h.

VN=298 cm³ /g; MFI (230/2)=2.8 dg/min, m.p. 132° C. Ethylene content:3.8% by weight.

Example P

Example O was repeated using 1-hexene as comonomer. The metalloceneactivity was 476 kg copolymer/g metallocene×h. The hexene content in therandom copolymer thus prepared was 4.8% by weight.

Example Q

Example O was repeated using 4-methyl-1-pentene as comonomer. Themetallocene activity was 378 kg copolymer/g metallocene×h, themethylpentene content was 5.3% by weight.

Example R

Example O was repeated, but 250 g of ethylene and 150 ml of5-ethylidene-2-norbornene were metered into the reactor to prepare aterpolymer rubber. The polymerization temperature was 50° C. Themetallocene activity was 282 kg polymer/g metallocene×h.

The following properties were determined on the polymer: 39.8% by weightethylene content and 5.4% by weight ethylidenenorbornene content, glasstransition temperature T_(g) =-55.4° C.

Example S

Example R was carried out without addition of ethylidenenorbornene, thepolymerization temperature was 60° C. and the amount of ethylene usedwas 500 g. The metallocene activity was 598 kg ethylene-propylenerubber/g metallocene×h.

The following properties were determined on the polymer: 52.2% by weightethylene content, glass transition temperature T_(g) =-53.9° C.

Example T

A dry 150 dm³ reactor was flushed with nitrogen and charged at 20° C.with 100 dm³ of a de-aromatized petroleum fraction having a boilingrange from 100° to 120° C. The gas space was then flushed free ofnitrogen by pressurizing with 2 bar of propylene and depressurizing 5times. After addition of 50 1 of liquid propylene, 64 cm³ ofmethylaluminoxane solution in toluene (corresponding to 100 mmol of Al)were added and the reactor contents were heated to 50° C. A hydrogencontent in the reactor gas space of 1.5% was set by metering in hydrogenand subsequently kept constant during the entire propylenepolymerization time by metering in further amounts (gas chromatography,on-line measurement). 25 mg of the metallocenedimethylsilanediyl(2-methyl-4-phenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)zirconiumdichloride were dissolved in 16 cm³ of methylaluminoxane solution intoluene (corresponding to 25mmol of Al) and, after 15 minutes, added tothe reactor.

By means of cooling, the reactor was maintained at a polymerizationtemperature of 50° C. for 5 hours. After venting hydrogen and propyleneto a propylene pressure of 1.5 bar in the reactor, the polymerizationwas continued after addition of 2.0 kg of ethylene for a further 3 hoursat 50° C.

The contents of the reactor were discharged onto a pressure filter, theproduct was separated off from residual suspension medium by means ofsteam distillation and was dried for 24 hours at 80° C./200 mbar. Thisgave 19.3 kg of block copolymer powder, corresponding to a metalloceneactivity of 96.5 kg copolymer/g metallocene×h. The block copolymercontained 8.9% by weight of ethylene, fractionation gave a content of19.8% by weight of ethylene/propylene rubber, the glass transitiontemperature of the rubber was -52.7° C. The MFI (230/2) of the totalpolymer was 46 dg/min.

Example U

Use of a supported catalyst system:

a) Preparation of the supported cocatalyst

The supported cocatalyst was prepared as described in EP 92 107 331.8 inthe following manner in a stainless steel reactor of explosion-protecteddesign having a pumped circulation system of 60 bar pressure rating,with inert gas supply, temperature control by means of jacket coolingand a second cooling circuit via a heat exchanger on the pumpedcirculation system. The pumped circulation system drew the reactorcontents via a connection in the bottom of the reactor using a pump,pressed it into a mixer and through a rising line via a heat exchangerback into the reactor. The mixer was connected in such a way that in theinlet there was a constricted tube cross-section where an increased flowvelocity arose and into the turbulence zone of which there was led,axially and counter to the flow direction, a narrow feed line throughwhich, in a pulsed manner, each of a defined amount of water and 40 barof argon were able to be fed. The reaction was monitored via a sampleron the pumped circuit.

The abovedescribed reactor having a volume of 16 dm³ was initiallycharged with 5 dm³ of decane under inert conditions. 0.3 dm³ (=3.1 mol)of trimethylaluminum were added at 25° C. 250 g of silica gel SD 3116-30(Grace AG), which were dried beforehand at 120° C. in an argon fluidizedbed, were metered into the reactor through a solids funnel anddistributed homogeneously by means of the stirrer and the pumpedcirculation system. A total amount of 45.9 g of water was added to thereactor over a period of 2 hours in portions of 0.1 cm³, each every 15seconds. The pressure, arising from argon and the gases evolved, waskept constant at 10 bar by means of pressure regulating valves. Afterall the water had been introduced, the pumped circulation system wasswitched off and the stirring was continued for a further 5 hours at 25°C. The solvent was removed by means of a pressure filter and thecocatalyst solid was washed with decane. It was then dried in vacuo. Theisolated solid contains 19.2% by weight of aluminum. 15 g of this solid(107 mmol of Al) were suspended in 100 cm³ of toluene in a stirrablevessel and cooled to -30° C. At the same time, 200 mg (0.317mmol) of Me₂Si(2-methyl-4-phenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl.sub.2were dissolved in 75 cm³ of toluene and added dropwise to the suspensionover a period of 30 minutes. The suspension was slowly warmed up to roomtemperature while stirring, taking on a red color. It was subsequentlystirred for 1 hour at 40° C. and, after cooling to room temperature, themixture was filtered and the solid was washed 3 times with 100 cm³ oftoluene each time and once with 100 cm³ of hexane. The remaining filterresidue which was moist with hexane was dried in vacuo. This gave 13.7 gof free-flowing, pale red, supported catalyst. Analysis gave a contentof 10.5 mg of zirconocene per gram of catalyst.

b) Polymerization

1.0 g of the catalyst prepared under a) were suspended in 25 cm³ of ade-aromatized petroleum fraction having a boiling range from 100° to120° C.

In parallel thereto, a dry 24 dm³ reactor was flushed first withnitrogen and subsequently with propylene and was charged with 12 dm³ ofliquid propylene and with 1.5 dm³ of hydrogen. 3 cm³ oftriisobutylaluminum (12 mmol) were then diluted with 30 ml of hexane,added to the reactor and the mixture was stirred for 15 minutes at 30°C. Subsequently, the catalyst suspension was added to the reactor, themixture was heated to the polymerization temperature of 80° C. (10°C./min) and the polymerization system was maintained at 80° C. for 1hour by means of cooling. The polymerization was stopped by addition of20 ml of isopropanol. The excess monomer was vented, the polymer wasdried in vacuo. This gave 2.28 kg of polypropylene powder. Themetallocene activity was thus 217 kg PP/g met.×h.

VN=235 cm³ /g; M_(w) =305,000 g/mol, M_(w) / M_(n) =2.2; MFI (230/2)=7.4dg/min; m.p. 152° C.

Powder morphology: no fines<200 μm, average particle diameter d₅₀ =650μm, narrow particle size distribution s=ln(d₅₀ /d₁₆)=0.28, bulk density485 g/dm³.

We claim:
 1. A metallocene compound of the formula I ##STR11## where M²is a metal of the group IVb, Vb or VIb of the Periodic Table,R¹ and R²are identical or different and are a hydrogen atom, a C₁ -C₁₀ -alkylgroup, a C₁ -C₁₀ -alkoxy group, a C₆ -C₁₀ -aryl group, a C₆ -C₁₀-aryloxy group, a C₂ -C₁₀ -alkenyl group, a C₇ -C₄₀ -arylalkyl group, aC₇ -C₄₀ -alkylaryl group, a C₈ -C₄₀ -arylalkenyl group or a halogenatom, R³ are identical or different and are a hydrogen atom, a halogenatom, a C₁ -C₁₀ -alkyl group which can be halogenated, a C₆ -C₁₀ -arylgroup, a C₂ -C₁₀ -alkenyl group, a C₇ -C₄₀ -arylalkyl group, a C₇ -C₄₀-alkyloxy group, a C₈ -C₄₀ -arylalkenyl group, a --NR₂ ¹⁰, --OR¹⁰,--SR¹⁰, --OSiR₃ ¹⁰, --SiR₃ ¹⁰ or --PR₂ ¹⁰ radical, where R¹⁰ is ahalogen atom, a C₁ -C₁₀ -alkyl group or a C₆ -C₁₀ -aryl group, R⁴ areidentical or different and are a hydrogen atom, a halogen atom, a C₁-C₂₀ -alkyl group, a C₁ -C₂₀ -fluoroalkyl group, a C₆ -C₃₀ -aryl group,a C₆ -C₃₀ -fluoroaryl group, a C₁ -C₂₀ -alkoxy group, a C₂ -C₂₀ -alkenylgroup, a C₇ -C₄₀ -arylalkyl group, a C₈ -C₄₀ -arylalkenyl group, a C₇-C₄₀ -alkylaryl group, a --NR₂ ¹⁰, --OR¹⁰, --SR¹⁰, --OSiR₃ ¹⁰, --SiR₃ ¹⁰or --PR₂ ¹⁰ radical, where R¹⁰ is a halogen atom, a C₁ -C₁₀ -alkyl groupor a C₆ -C₁₀ -aryl group, or two or more radicals R⁴ together with theatoms connecting them form a ring system, R⁵ is a hydrogen atom, ahalogen atom, a C₁ -C₁₀ -alkyl group which can be halogenated, a C₆ -C₁₀-aryl group, a C₂ -C₁₀ -alkenyl group, a C₇ -C₄₀ -arylalkyl group, a C₇-C₄₀ -alkyloxy group, a C₈ -C₄₀ -arylalkenyl group, a --NR₂ ¹⁰, --OR¹⁰,--SR¹⁰, --OSiR₃ ¹⁰, --SiR₃ ¹⁰ or --PR₂ radical, where R¹⁰ is a halogenatom, a C₁ -C₁₀ -alkyl group or a C₆ -C₁₀ -aryl group, R⁶ are identicalor different and are a hydrogen atom, a halogen atom, a C₁ -C₂₀ -alkylgroup which can be halogenated, a C₆ -C₃₀ -aryl group, a C₂ -C₁₀-alkenyl group, a C₇ -C₄₀ -arylalkyl group, a C₇ -C₄₀ -alkyloxy group, aC₈ -C₄₀ -arylalkenyl group, a --NR₂ ¹⁰, --OR¹⁰, --SR¹⁰, --OSiR₃ ¹⁰,--SiR₃ ¹⁰ or --PR₂ ¹⁰ radical, where R¹⁰ is a halogen atom, a C₁ -C₁₀-alkyl group or a C₆ -C₁₀ -aryl group, R⁷ is ##STR12## ═BR¹¹, ═AIR¹¹,--Ge--, --Sn--, --O--, --S--, ═SO, ═SO₂, ═NR¹¹, ═CO, ═PR¹¹ or ═P(O)R¹¹,where R¹¹, R¹² and R¹³ are identical or different and are a hydrogenatom, a halogen atom, a C₁ -C₂₀ -alkyl group, a C₁ -C₂₀ -fluoroalkylgroup, a C₆ -C₃₀ -aryl group, a C₆ -C₃₀ -fluoroaryl group, a C₁ -C₂₀-alkoxy group, a C₂ -C₂₀ -alkenyl group, a C₇ -C₄₀ -arylalkyl group, aC₈ -C₄₀ -arylalkenyl group, a C₇ -C₄₀ -alkylaryl group, or R¹¹ and R¹²or R¹¹ and R¹³ in each case together with the atoms connecting them forma ring, M¹ is silicon, germanium or tin, R⁸ and R⁹ are identical ordifferent and are a hydrogen atom, a halogen atom, a C₁ -C₂₀ -alkylgroup, a C₁ -C₂₀ -fluoroalkyl group, a C₆ -C₃₀ -aryl group, a C₆ -C₃₀-fluoroaryl group, a C₁ -C₂₀ -alkoxy group, a C₂ -C₂₀ -alkenyl group, aC₇ -C₄₀ -arylalkyl group, a C₈ -C₄₀ -arylalkenyl group, a C₇ -C₄₀-alkylaryl group, or R⁸ and R⁹ together with the atoms connecting themform a ring, m and n are identical or different and are zero, 1 or 2,where m plus n is zero, 1 or 2, wherein at least one of the radicals R⁴and R⁵ is not hydrogen.
 2. A metallocene compound as claimed in claim 1,wherein M² is zirconium, R¹ and R² are identical or different and aremethyl or chlorine, R³ is hydrogen, R⁴ is a hydrogen atom, a C₁ -C₂₀-alkyl group or a C₆ -C₃₀ -aryl group, or two or more radicals R⁴together with the atoms connecting them form a ring system, R⁵ ishydrogen or a C₁ -C₁₀ -alkyl group, R⁶ is a hydrogen atom, a C₁ -C₁₀-alkyl group, a C₆ -C₂₀ -aryl group or a radical SiR¹⁰ ₃, where R¹⁰ is aC₁ -C₁₀ -alkyl group, R⁷ is a radical ##STR13## where R¹¹ and R¹² areidentical or different and are a C₁ -C₂₀ -alkyl group or a C₆ -C₃₀ -arylgroup, R⁸ and R⁹ are identical or different and are a hydrogen atom or aC₁ -C₃₀ -alkyl group, m plus n is zero or 1, and at least one of theradicals R⁶ and also at least one of the radicals R⁵ and R⁴ is nothydrogen.
 3. A metallocene compound as claimed in claim 1, wherein M² iszirconium, R¹ and R² are identical or different and are methyl orchlorine, R³ is hydrogen, R⁴ is a hydrogen atom, a C₁ -C₂₀ -alkyl groupor a C₆ -C₃₀ -aryl group, or two or more radicals R⁴ together with theatoms connecting them form a ring system, R⁵ is a hydrogen atom or a C₁-C₁₀ -alkyl group, R⁶ is a hydrogen atom, a C₁ -C₁₀ -alkyl group, a C₆-C₂₀ -aryl group or a radical SiR¹⁰ ₃, where R¹⁰ is a C₁ -C₁₀ -alkylgroup, R⁷ is a radical ##STR14## where R¹¹ and R¹² are identical ordifferent and are a C₁ -C₂₀ -alkyl group or a C₆ -C₃₀ -aryl group, R⁸and R⁹ are identical or different and are a hydrogen atom or a C₁ -C₃₀-alkyl group, m+n is zero or 1, and at least one of the radicals R⁵ andR⁴ is not hydrogen.
 4. A catalyst comprising at least one metallocenecompound as claimed in claim 1 and at least one cocatalyst compound. 5.A catalyst comprising at least one metallocene compound as claimed inclaim 1 wherein the metallocene compound is prepolymerized.
 6. Acatalyst comprising at least one metallocene compound as claimed inclaim 1, wherein the metallocene compound is supported.
 7. Themetallocene as claimed in claim 1, wherein said metallocene isdimethylsilanediyl(4,5-benzo-1-indenyl) (cyclopentadienyl)ZrCl₂.
 8. Acatalyst comprising the metallocene as claimed in claim 7, and acocatalyst.
 9. The metallocene as claimed in claim 1, wherein saidmetallocene is selected from the group consistingofdimethylsilanediyl(2-methyl-4,5-benzo-1-indenyl)(3-methyl-1-cyclopentadienyl)ZrCl₂,dimethylmethylene(2-methyl-1-indenyl)(cyclopentadienyl) ZrCl₂,dimethylmethylene(4,5-benzo-1-indenyl)(cyclopentadienyl) ZrCl₂,dimethylgermyl(4,5-benzo-1-indenyl)(cyclopentadienyl) ZrCl₂,dimethylsilanediyl(2-methyl-4,5-benzo-1-indenyl) cyclopentadienyl)ZrCl₂,dimethylsilanediyl(2-methyl-4-phenyl-1-indenyl)(3-methyl-1-cyclopentadienyl)ZrCl₂,dimethylgermyl(2-methyl-4-phenyl-1-indenyl)(cyclopentadienyl)ZrCl₂,dimethylsilanediyl(4-phenyl-1-indenyl)(3-methyl-1-cyclopentadienyl)ZrCl.sub.2,dimethylsilanediyl(4-phenyl-1-indenyl)(cyclopentadienyl)ZrCl₂,dimethylmethylene(4-phenyl-1-indenyl)(cyclopentadienyl)ZrCl₂ anddimethylsilanediyl(4,5-benzo-1-indenyl)(cyclopentadienyl)ZrCl₂.
 10. Themetallocene as claimed in claim 1, wherein said metallocene is selectedfrom the group consistingofdimethylsilanediyl(2-methyl-4-phenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,dimethylsilanediyl(2-methyl-4-phenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrMeCl,dimethylsilanediyl(2-methyl-4-phenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrMe₂,dimethylsilanediyl(2-methyl-4-phenyl-1-indenyl)(2-methyl-1-cyclopentadienyl)ZrCl₂,dimethylsilanediyl(2-methyl-4-phenyl-1-indenyl)(3,5-dimethyl-1-cyclopentadienyl)ZrCl₂,dimethylsilanediyl(2-methyl-4-phenyl-1-indenyl)(2,5-dimethyl-3-t-butyl-1-cyclopentadienyl)ZrCl₂,1,2-ethanediyl(2-methyl-4-phenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,phenyl(methyl)silanediyl(2-methyl-4-phenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,diphenylsilanediyl(2-methyl-4-phenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,dimethylsilanediyl(2-ethyl-4-phenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,dimethylsilanediyl(2,4-diphenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,dimethylsilanediyl(2-ethyl-4-(1-naphthyl)-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,dimethylgermyl(2-methyl-4-phenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,methyl(vinyl)silanediyl(2-methyl-4-phenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,phenyl(vinyl)silanediyl(2-methyl-4-phenyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,dimethylgermyl(2-ethyl-4-(1-naphthyl)-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,dimethylsilanediyl(2-methyl-4-(1-naphthyl)-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,dimethylsilanediyl(2-methyl-4-(2-naphthyl)-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,dimethylsilanediyl(2-methyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,dimethylsilanediyl(2-methyl-4-isopropyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,dimethylsilanediyl(2-methyl-4,5-benzo-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,dimethylsilanediyl(2-methyl-α-acenaphth-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,dimethylsilanediyl(2-methyl-4,6-diisopropyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,dimethylsilanediyl(2,4,6-trimethyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,dimethylsilanediyl(2,5,6-trimethyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,dimethylsilanediyl(2,4,5-trimethyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂,dimethylsilanediyl(2,5-dimethyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂anddimethylsilanediyl(2,6-dimethyl-1-indenyl)(2,3,5-trimethyl-1-cyclopentadienyl)ZrCl₂.11. A catalyst comprising the metallocene as claimed in claim 9, and acocatalyst.
 12. A catalyst comprising the metallocene as claimed inclaim 10, and a cocatalyst.
 13. The catalyst as claimed in claim 8,wherein said cocatalyst is an aluminoxane.
 14. The catalyst as claimedin claim 11, wherein said cocatalyst is an aluminoxane.
 15. The catalystas claimed in claim 12, wherein said cocatalyst is an aluminoxane.
 16. Asupported and/or prepolymerized catalyst component comprising at leastone metallocene compound as claimed in claim
 7. 17. A supported and/orprepolymerized catalyst component comprising at least one metallocenecompound as claimed in claim
 9. 18. A supported and/or prepolymerizedcatalyst component comprising at least one metallocene compound asclaimed in claim 10.